[FFmpeg-devel] [PATCH v2] avfilter: add QSV variants of the stack filters

[Xiang, Haihao]

On Wed, 2021-08-04 at 09:17 +0000, Soft Works wrote:
> > -----Original Message-----
> > From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> > Haihao Xiang
> > Sent: Wednesday, 4 August 2021 10:33
> > To: ffmpeg-devel at ffmpeg.org
> > Cc: Haihao Xiang <haihao.xiang at intel.com>
> > Subject: [FFmpeg-devel] [PATCH v2] avfilter: add QSV variants of the stack
> > filters
> > 
> > Include hstack_qsv, vstack_qsv and xstack_qsv, some code is copy and
> > pasted from other filters
> > 
> > Example:
> > $> ffmpeg -hwaccel qsv -c:v hevc_qsv -i input.h265 -filter_complex
> > "[0:v][0:v]hstack_qsv" -f null -
> > ---
> 
> [...]
> 
> > +
> > +/*
> > + * Callback for qsvvpp
> > + * @Note: qsvvpp composition does not generate PTS for result frame.
> > + *        so we assign the PTS from framesync to the output frame.
> > + */
> > +
> > +static int filter_callback(AVFilterLink *outlink, AVFrame *frame)
> > +{
> > +    QSVStackContext *sctx = outlink->src->priv;
> > +
> > +    frame->pts = av_rescale_q(sctx->fs.pts,
> > +                              sctx->fs.time_base, outlink->time_base);
> > +    return ff_filter_frame(outlink, frame);
> > +}
> 
> If the surface.Data.TimeStamp gets overwritten by libMFX, why not copy 
> the PTS from the input frame in ff_qsvvpp_filter_frame ?
> 
> That would apply the timestamp from the last input, though. Preferably would
> it
> be taken from the first input instead. For 2-n, you could perhaps clone the
> frames and 
> assign the pts from the first input's frame?

Thanks for the comment and suggestion. This callback function was copy-and-
pasted from overlay_qsv filter because MSDK composition is also used by this
filter, I'd like to use the same way to generate pts for these filters, but I'll
try your suggestion for these filters in the future. 

Regards
Haihao